The present invention relates to ice accumulation occurring on the rotor blades of a wind turbine; and more particularly a method and system for detecting asymmetric icing.
Wind turbines are commonly installed in areas where the climatic conditions allow for ice accumulation (hereinafter icing). Icing on the rotor blades (hereinafter blades) of a wind turbine typically leads to several problems including a reduction in power output; and higher stresses on several components. Icing may be divided into two forms, symmetric (icing on all blades) and asymmetric, (icing on some blades). Asymmetric icing increases the wind turbine tower vibration, and increases the lateral tower acceleration. Asymmetric icing may also yield a rotor-mass imbalance leading to higher fatigue loads, and thus requiring more robust and expensive wind turbine components.
Current systems of detecting asymmetric icing typically require additional hardware such as sensors, anemometers, piezoelectric transducers, or the like. Moreover, wind turbine operators generally must purchase and install this additional hardware.
There are a few problems with the current systems and methods for addressing icing. The requirement of additional hardware increases the installation and operational costs of the wind turbine. Furthermore, for geographical areas having an average yearly temperature above freezing, the additional costs associated with detecting asymmetric icing may prohibit wind turbine operation.
For the foregoing reasons, there is a need for a method and system for detecting asymmetric icing utilizing existing wind turbine hardware. The method should not require additional hardware. Furthermore, the method should incorporate lateral tower acceleration data to detect asymmetric icing.